Long-term alterations in μ, δ and κ opioidergic receptors following middle cerebral artery occlusion in mice

Alterations in the opioidergic system may play a role in the molecular mechanisms underlying neurochemical responses to cerebral ischaemia. The present study aimed to determine the delayed expression of μ, δ and κ opioid receptors, following 1, 2, 7, and 30 days of middle cerebral artery occlusion (MCAO) in mice. Using quantitative autoradiography, we highlighted significant decreases in μ, δ and κ opioid receptor expression in ipsilateral cortices from day 1 post-MCAO. Moreover, in contralateral nucleus lateralis thalami pars posterior, ipsi- and contralateral nucleus medialis dorsalis thalami, and ipsilateral substantia nigra, pars reticulata (SNr), κ receptors were increased; μ receptor densities were decreased in nucleus ventralis thalami, pars posterior (VThP), and SNr. δ-Binding sites were increased in the striatum on day 30 post-MCAO. The alterations in opioid receptors in cortical infarcts were correlated with strong histological damage. Further reductions in opioid receptor densities in cortical infarcts were observed at later time points. In subcortical brain regions, opioid receptor densities were also altered but no histological damage was seen, except in the VThP, in which cell density was increased on day 30. Delayed reductions in opioid receptor densities in the infarct appeared as the continuation of the early processes previously demonstrated. However, changes in subcortical opioid receptor expression may correlate with neuronal alterations in remote brain regions. Changes in opioidergic receptor expression in these regions may be involved in the long-term consequences of stroke and could be used as biomarker of neuronal alteration through the use of imaging techniques in the clinic. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

orrelation of aquaporin-4 expression to blood-brain barrier permeability in rats with focal cerebral ischemia**★

BACKGROUND： Ischemic cerebrovascular disease causes injury to the blood-brain barrier. The occurrence of brain edema is associated with aquaporin expression following cerebral ischemia/reperfusion. OBJECTIVE： To analyze the correlation of aquaporin-4 expression to brain edema and blood-brain barrier permeability in brain tissues of rat models of ischemia/reperfusion. DESIGN, TIME AND SETTING： The randomized control experiment was performed at the Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical College, China from December 2006 to October 2007. MATERIALS： A total of 112 adult, male, Sprague-Dawley rats, weighing 220-250 g, were used to establish rat models of middle cerebral artery occlusion and reperfusion by the suture method. Rabbit anti-aquaporin-4 （Santa Cruz, USA） and Evans blue （Sigma, USA） were used to analyze the tissue. METHODS： The rats were randomized into sham-operated （n = 16） and ischemia/reperfusion （n = 96） groups. There were 6 time points in the ischemia/reperfusion group, comprising 4, 6, 12, 24, 48, and 72 hours after reperfusion, with 16 rats for each time point. Rat models in the sham-operated group at 4 hours after surgery and rat models in the ischemia/reperfusion group at different time points were equally and randomly assigned into 4 different subgroups. MAIN OUTCOME MEASURES： Brain water content on the ischemic side and the control side was measured using the dry-wet weight method. Blood-brain barrier function was determined by Evans Blue. Aquaporin-4 expression surrounding the ischemic focus, as well as the correlation of aquaporin-4 expression with brain water content and Evans blue staining, were measured using immunohistochemistry and Western blot analysis. RESULTS： Brain water content on the ischemic side significantly increased at 12 hours after reperfusion, reached a peak at 48 hours, and was still high at 72 hours. Brain water content was greater on the ischemic hemispheres, compared with the control hemispheres at 6, 12, 24, 48, an     

Absent middle cerebral artery signal in transcranial color-coded sonography: a reliable indicator of occlusion?

BACKGROUND: Assess the accuracy of transcranial color-coded sonography (TCCS) for detecting middle cerebral artery (MCA) stem occlusion and compare it with cerebral angiography. METHODS: This study enrolled a series of patients who received TCCS and cerebral angiography at the Department of Neurology in Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan, between January 1997 and July 2003. MCA stem occlusion was diagnosed based on digital subtraction angiography and/or computed tomographic angiography. The effect of the supplying artery on the insonation of MCA stem was considered. The sonographic criteria for MCA stem occlusion were defined as absent MCA stem signal + visible signal on the reference arteries, including ipsilateral posterior cerebral artery, ipsilateral anterior cerebral artery or contralateral MCA stem. RESULTS: A total of 419 consecutive patients were enrolled. Factors that significantly influenced MCA stem insonation included > or =50% ipsilateral carotid artery stenosis, > or =50% MCA stem stenosis, female gender, and age > or =60 years. Comparing patients with <50% and those with > or =50% carotid stenosis, the MCA stem insonation rate was significantly reduced from 69.1% to 45.6% (p < 0.001). In patients with <50% ipsilateral carotid artery stenosis, the sonographic criteria had a positive predictive value of 10.5% and a negative predictive value of 98.9%, and could predict MCA stem occlusion with high specificity but low sensitivity (specificity = 89.6, sensitivity = 54.5, overall accuracy = 88.9, p < 0.001). CONCLUSION: Absent MCA stem signal may result from MCA stem occlusion/tight stenosis and tight stenosis of ipsilateral carotid arteries, and has a limited value in detecting MCA stem occlusion. TCCS can be useful in identifying nonoccluded MCA stem, and cerebral angiography is necessary to confirm MCA stem occlusion.     

Effect of Fujian tablet on the expression of Nogo-A mRNA in the cervical spinal cord of middle cerebral artery occlusion model rats

BACKGROUND: Inhibiting the expression of Nogo-A in cervical spinal cord by use of interaction of antigen and antibody can help the remodeling of corticospinal projection of focal cerebral ischemia model rats to facilitate neurological recovery, which provides a new possible mechanism for drugs to promote neurological recovery. However, the effects of drugs on the expression of Nogo-A in cervical spinal cord are still unclear. OBJECTIVE: To observe the effect of Fujian tablet on the expression of Nogo-A mRNA in cervical spinal cords of middle cerebral artery occlusion (MCAO) rats, and to investigate the possible regulatory effect of Fujian tablet on the regenerated microenvironment of spinal conduction bundle. DESIGN: A randomized and controlled trial taking Wistar rats as experimental animals. SETTING: Department of Neurology, Affiliated Hospital of Shandong University of Traditional Chinese Medicine. MATERIALS: This experiment was carried out in the laboratory of Shandong Academy of Medical Science between June 2005 and July 2006. A total of 40 healthy male Wistar rats, aged 12 weeks, weighing 250–300 g, were provided by the Experimental Animal Center of Shandong University. Fujian tablets (main components: Heshouwu, Yinyanghuo, etc) were provided by office of Pharmaceutics of Shandong University of traditional Chinese medicine. Nogo-A detection kit was provided by Wuhan Boster Biotechnology Co.,Ltd., and batch number was 040309009. This experiment was approved by Local Animal Ethics Committee. METHODS: Forty male rats were randomly divided into 4 groups, with 10 in each: normal group, sham-operation group, model group and administration group. Rats in the administration group and model group were subjected to MCAO. Rats in the sham-operation group underwent the same craniotomy, and their middle cerebral arteries (MCA) were not occluded. Rats in the normal group were untouched. Rats in administration group were intragastrically administrated with the solution of Fujian tablet at a dose of 9 g/kg and others were given equal dosage of normal saline two days later. The treatments were done once a day and the course totaled 2 weeks. MAIN OUTCOME MEASURES: The expression of Nogo-A mRNA in slices of cervical spinal cords. RESULTS: Forty rats were involved in the final analysis. The expression of Nogo-A mRNA in the cervical spinal cord of rats in the administration group and model group was significantly decreased as compared with that in the normal group (P < 0.01 and P < 0.05, respectively). The expression of Nogo-A mRNA in the administration group was also significantly weaker than that in the model group（P < 0.05）. CONCLUSION: Fujian tablet can inhibit the expression of Nogo-A mRNA in cervical spinal cords of MCAO rats, which facilitates regeneration and remodeling of cervical spinal cords.     

17β-estradiol attenuates breakdown of blood-brain barrier and hemorrhagic transformation induced by tissue plasminogen activator in cerebral ischemia

Tissue plasminogen activator (tPA) remains the only approved thrombolytic agent for the early treatment of ischemic stroke. However, treatment with tPA may lead to disruption of the blood–brain barrier and hemorrhagic transformation. 17β-estradiol (E2) has demonstrated efficacy in reduction of infarct volume in ischemic stroke models. The effects of acute administration of E2 on permeability of the blood–brain barrier and its ability to prevent hemorrhagic transformation in ischemic rats treated with tPA have not previously been studied. Here, we show that neurological deficits, brain water content, and Evan's blue extravasation were increased in ovariectomized female Wistar rats treated with tPA and attenuated in rats receiving E2 + tPA. We also show that intracerebral hemoglobin and matrix metalloproteinase-9 activity were elevated with tPA treatment, and these increases were reduced by E2 treatment. Taken together, these data demonstrate that acute administration of E2 is capable of ameliorating some of the adverse effects of tPA administration, including the increase of matrix metalloproteinase-9 activity, blood–brain barrier permeability, and hemorrhagic transformation. These findings suggest a potential role for estrogen in thrombolytic treatment for ischemic stroke.     

Regional cerebral perfusion and ischemic status after standard superficial temporal artery–middle cerebral artery (STA-MCA) bypass surgery in ischemic cerebrovascular disease

Background and purpose  

Standard superficial temporal artery–middle cerebral artery (STA-MCA) bypass surgery is an effective treatment for ischemic cerebrovascular diseases, including moyamoya disease and occlusive cerebrovascular disease. Our purpose in this study was to evaluate the ischemic status based on the imaging modality of computed tomographic perfusion (CTP) before and after STA-MCA bypass in patients with moyamoya disease and occlusive cerebrovascular disease.     

Identification of blood-brain barrier function following subarachnoid hemorrhage in rats at different stages*☆

BACKGROUND： Recent studies have indicated that blood-brain barrier （BBB） disruption following subarachnoid hemorrhage （SAH） significantly correlates with the development of brain injury and poor prognosis of patients subjected to SAH. OBJECTIVE： To investigate both functional and structural changes related to BBB in various phases after SAH in rats through quantitative and qualitative methods. DESIGN, TIME AND SETTING： This experiment, a completely randomized design and controlled experiment, was performed at the Department of Neurosurgery, the Second Affiliated Hospital of Chongqing University of Medical Sciences from June 2006 to March 2007. MATERIALS： A total of 128 female, healthy, Sprague-Dawley rats were selected for this study. Main reagents and instruments： Evans Blue dye （Sigma Company, USA）, fluorescence spectrophotometer （Shimadzu Company, Japan）, and transmission electron microscope （Olympus Company, Japan）. METHODS： The included 128 rats were randomly divided into two groups： sham-operated group （n = 16） and SAH group （n = 112）. Rats in the SAH group were divided into seven subgroups： 6, 12, 24, 36, 48, 60, and 72 hours after SAH （16 rats for each time point）. Experimental SAH was induced by blood injection into the pre-chiasmatic cistern （300 μ L）. The sham-operated group received an equivalent volume of normal saline solution （300 μ L） injected into the subarachnoid space. MAIN OUTCOME MEASURES： Brain tissue water content was determined by the wet-dry method. BBB permeability in the cerebral cortex was determined by Evans Blue dye and fluorescent spectrophotometer. The ultrastructural changes in BBB were observed with transmission electron microscope. RESULTS： Compared with the sham-operated group, SAH induced a significant increase in brain water content between 24 and 60 hours （F = 888.32, P 〈 0.05）. Brain water content increased to a maximum by 36 hours after SAH, normalizing by 72 hours. Evans Blue content in the cerebral corte     

Neurovascular protection by targeting early blood–brain barrier disruption with neurotrophic factors after ischemia–reperfusion in rats

The ‘new penumbra'' concept imbues the transition between injury and repair at the neurovascular unit with profound implications for selecting the appropriate type and timing of neuroprotective interventions. In this conceptual study, we investigated the protective effects of pigment epithelium-derived factor (PEDF) and compared them with the properties of epidermal growth factor (EGF) in a rat model of ischemia–reperfusion injury. We initiated a delayed intervention 3 hours after reperfusion using equimolar amounts of PEDF and EGF. These agents were then administered intravenously for 4 hours following reperfusion after 1 hour of focal ischemia. Magnetic resonance imaging indices were characterized, and imaging was performed at multiple time points post reperfusion. PEDF and EGF reduced lesion volumes at all time points as observed on T₂-weighted images (T₂-LVs). In addition PEDF selectively attenuated lesion volume expansion at 48 hours after reperfusion and persistently modulated blood–brain barrier (BBB) permeability at all time points. Intervention with peptides is suspected to cause edema formation at distant regions. The observed T₂-LV reduction and BBB modulation by these trophic factors is probably mediated through a number of diverse mechanisms. A thorough evaluation of neurotrophins is still necessary to determine their time-dependent contributions against injury and their modulatory effects on repair after stroke.     

Characteristics of global cerebral ischemia models constructed by modified four-vessel occlusion in rats

INTRODUCTION The four-vessel occlusion method introduced by Pulsinelli et al [1] is widely used as an experimental model for reversible forebrain is- chemia in rats [2-15]. The model presented several advantages, which included ease of preparation, a high…     

Excellent rates of recanalization and good functional outcome after stent-based thrombectomy for acute middle cerebral artery occlusion. Is it time for a paradigm shift?

The natural history of untreated acute middle cerebral artery (MCA) occlusion is poor, with high rates of mortality (5–33%) and severe long-term disability (40–80% of survivors), despite therapy with intravenous tissue plasminogen activator. We analyzed outcomes in 31 consecutive patients with major ischemic stroke due to acute proximal MCA occlusion who were treated at the Hadassah-Hebrew University Medical Center from February 2010 to October 2012 by endovascular means, using the Solitaire stent (Covidien, Irvine, CA, USA) as a thrombectomy device. Patients had a mean age of 63.3 ± 16.2 years (range, 26–92). The admission National Institutes of Health Stroke Scale score was 19.5 ± 4.3 (median 20). Mean time from symptom onset to femoral artery puncture was 3.8 ± 1.1 hours (median 4 hours). Mean time to recanalization was 46.9 ± 11.1 minutes. Successful recanalization by means of stent-based thrombectomy alone was achieved in 90% of cases and reached 100% after combining definitive stent implantation in three patients. There was no arterial rupture or subarachnoid hemorrhage. Hemorrhagic transformation developed in seven patients (23%), but was symptomatic in only one. Post-procedure CT scan or MRI demonstrated >90% sparing of cortex at risk in all patients. Functional outcome at 90 day follow-up was modified Rankin Score 0–2 in 77% of all patients and 88% of patients younger than 80 years. Three patients (10%) died during hospitalization due to mesenteric event, sepsis, or pulmonary embolism. Our experience suggests that stent-based thrombectomy in selected patients for acute MCA occlusions is safe, very effective in terms of arterial recanalization, and associated with improved neurological outcome. If validated by other groups, endovascular treatment may be proposed as the therapy of choice for MCA occlusion.     

Expression of transforming growth factor-β1, 2, 3 isoforms and type I and II receptors in acute focal cerebral ischemia: an immunohistochemical study in rat after transient and permanent occlusion of middle cerebral artery

Transforming growth factor beta (TGF-β) is involved in the modulation of cell growth, differentiation and repair following injury of various organs. Previous studies on human autopsy material have indicated that TGF-β isoforms -β1, -β2 and -β3, and TGF-β receptor type I are expressed in various cells of necrotizing brain lesions like infarction and abscess. The present immunohistochemical study was designed to investigate changes that may occur with regard to TGF-β and its receptors type I and II in a rat model of focal brain ischemia induced by transient or permanent occlusion of the middle cerebral artery. Our findings indicate that at days 1 and 3 following such transient and permanent ischemia there is an up-regulation of TGF-β isoforms -β1, -β2 and -β3, and TGF-β receptor types I and II mainly in the perifocal neurons, reactive astroglial cells, endothelial cells and macrophages. Received: 20 May 1998 / Revised: 14 August, 2 November 1998 / Accepted: 3 November 1998     

Superficial temporal artery–middle cerebral artery bypass surgery in a pediatric giant intracranial aneurysm presenting as migraine-like episodes

Introduction  Aneurysms of the intracranial arteries in the pediatric population are reportedly rare. There is a male predominance, association with connective tissue disorders, as well as bacterial, mycotic infections, and trauma. Results and discussion  Common sites of presentation are the internal carotid artery bifurcation, posterior circulation, and distal segment of middle cerebral artery. Clinical manifestations can vary from seizures and subarachnoidal hemorrhage to headache, irritability, lethargy, vomiting, or focal motor deficits. Current treatment modalities encompass endovascular or surgical approach. Conclusion  We present a case report on an 11-year-old girl with migraine-like episodes due to an underlying giant fusiform middle cerebral artery aneurysm treated successfully with two superficial temporal artery–middle cerebral artery bypasses.     

Genetic inhibition of PKCε attenuates neurodegeneration after global cerebral ischemia in male mice

Global cerebral ischemia that accompanies cardiac arrest is a major cause of morbidity and mortality. Protein Kinase C epsilon (PKCε) is a member of the novel PKC subfamily and plays a vital role in ischemic preconditioning. Pharmacological activation of PKCε before cerebral ischemia confers neuroprotection. The role of endogenous PKCε after cerebral ischemia remains elusive. Here we used male PKCε-null mice to assess the effects of PKCε deficiency on neurodegeneration after transient global cerebral ischemia (tGCI). We found that the cerebral vasculature, blood flow, and the expression of other PKC isozymes were not altered in the PKCε-null mice. Spatial learning and memory was impaired after tGCI, but the impairment was attenuated in male PKCε-null mice as compared to male wild-type controls. A significant reduction in Fluoro-Jade C labeling and mitochondrial release of cytochrome C in the hippocampus was found in male PKCε-null mice after tGCI. Male PKCε-null mice expressed increased levels of PKCδ in the mitochondria, which may prevent the translocation of PKCδ from the cytosol to the mitochondria after tGCI. Our results demonstrate the neuroprotective effects of PKCε deficiency on neurodegeneration after tGCI, and suggest that reduced mitochondrial translocation of PKCδ may contribute to the neuroprotective action in male PKCε-null mice.